Freelance Senior OR Junior Full Stack Developer – React / Next.
Js / Node.
Js – BarcelonaYou will collaborate closely with the Tech Lead, Product Owner, UX Designer, and Data team to design, develop, and deliver high-quality features within an agile environment.
ResponsibilitiesDevelop and maintain complex, data-heavy user interfaces usingReact and Next.
JsBuild and optimisereusable componentsand contribute to the internal UI libraryDesign and integrateREST APIsand WebSocket endpointsEnsure code quality throughclean architecture and best practicesWriteunit and integration tests(Jest / Testing Library) Collaborate with Product, UX, and Data to deliver features end-to-endParticipate in architecture discussions and decision-makingTroubleshoot and resolve issues across the stackContribute to CI/CD processes and development workflow improvementsMaintain documentation on ConfluenceRequired Qualifications 3-5+ years of experienceas a Full Stack or Front-End EngineerStrong hands-on experience withReact.
Js and Next.




JsExperience building and consumingREST APIsGood understanding of backend technologies (Node.
Js required; Python/FastAPIis a plus) Experience withcomponent libraries, design systems, or shared UI componentsFamiliarity with modern testing frameworks (Jest, Testing Library) Good understanding of performance, security, and scalability principlesComfortable working in cross-functional agile teamsStrong communication skills in EnglishNice to HaveExperience with container technologies ( Docker, AWS ECR/EKS, OpenShift) Experience with CI/CD pipelinesKnowledge of SonarQube, Checkmarx, or similar code quality toolsExperience in healthcare, pharma, or other regulated environmentsWhat

We Offer
Full-time freelance mission 3-month contract, renewable depending on performance and roadmapHybrid environment from BarcelonaSeniority levelMid-Senior levelEmployment typeFull-timeJob functionInformation TechnologyIndustriesPharmaceutical ManufacturingBarcelona, Catalonia, Spain

📌 Freelance Senior Or Junior Full Stack Developer (Madrid)
🏢 Jobtome
📍 Madrid